Time trends and inequalities of physical activity domains and sitting time in South America

Background We aimed to investigate time trends and inequalities of different physical activity (PA) domains and sitting time (ST) in adults from South American countries. Methods We included cross-sectional data of nationally representative surveys on adults (n = 597 843) from nine South American countries (Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Uruguay, and Venezuela), with data collection time frames ranging from 2005 to 2020. Data on different PA domains (leisure-time, transport, and occupational) and ST were assessed through questionnaires. Trends according to education level (quintiles), gender (m/w), and age group (18-34 years, 35-49 years, 50-64 years) were estimated for the harmonized indicators of nonzero PA in the different domains, ≥150 min/week of total PA and ≥8 hours/d of ST. Results Chile (2009/2010 = 78.9% vs 2016/2017 = 70.5%), and Peru (2009/2010 = 78.6% vs 2011 = 69.6%) reduced total PA, while Brazil (2013 = 57.3% vs 2019 = 67.0%) and Uruguay (2006 = 69.4% vs 2013 = 79.4%) increased, and Argentina and Venezuela maintained. There was an increasing trend for ST in Argentina, Peru, and Uruguay. Leisure-time PA increased in most countries (6/8 countries). Transport PA was relatively stable, while occupational PA presented mixed findings. Education inequalities increased over time for total and leisure-time PA, while age and gender inequalities were relatively constant. Conclusions Future South American countries' efforts may be warranted to promote PA and reduce ST in adults, while addressing inequalities when implementing actions.


Design
This is a cross-sectional, multi-country study conducted by the South American Physical Activity and Sedentary Behavior Network (SAPASEN). The SAPASEN aims to harmonize national representative data sets with physical activity and sedentary behavior indicators from South American countries [13]. After the first analyses [6,8], we identified nine countries with more than one survey along the time (from 2005-2019) with physical activity and/or sitting time and included data from Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Uruguay, and Venezuela.

Sample
We analyzed data from the following countries: Argentina (2005, 2009, Table S1 in the Online Supplementary Document.
Data of each country were pooled, excluding young and older people, including the age range between 18 and 64 years. The exceptions were the survey from Ecuador during 2011-2012, which only included younger than 60 years, both studies from Bolivia that included participants between 18 and 49 years and Uruguay's 2006 STEPS survey that included participants between 25 and 64 years. All samples were calculated through complex sampling, with several levels. More detailed sampling methodology can be found in Table S1 in the Online Supplementary Document.
After excluding participants older than 64 and younger than 18 years as well as missing data, the final sample was composed of 597 843 adults (more information on the sample size and missing data from each survey can be found in Table S1 in the Online Supplementary Document). Specific sampling weights originally calculated from each survey aiming the extrapolation of data for population characteristics representativity were used in the analyzes.

Physical activity and sitting time
The International Physical Activity Questionnaire (IPAQ) [14] was used in the surveys from Argentina, Colombia, Ecuador (2011-2012) Peru, and Venezuela, while the Global Physical Activity Questionnaire (GPAQ) [15] was used on surveys from Chile, Ecuador (2018) and Uruguay. Brazil used a specific questionnaire derived from another survey (Surveillance System for Risk and Protective Factors for Chronic Diseases by Telephone Survey -VIGITEL) [16]. There were questions regarding leisure-time, transportation, and occupational physical activity in all questionnaires. Bolivia included a specific question regarding leisure-time physical activity and another for sitting time. Argentina had the short version of the IPAQ but included questions about physical activity practice in each domain. The 2008 and 2015 surveys from Brazil, and the 2007-2008 survey from Peru only included questions regarding leisure-time physical activity. The surveys from Colombia and Ecuador (2011-2012) included questions regarding leisure-time and transport. Total sitting time (including leisure time, occupational and transport) was the indicator of sitting time in all the included surveys. The IPAQ, GPAQ and VIGITEL are validated questionnaires, while the specific questions used in Bolivia andPeru (2007-2008) were not previously validated [14][15][16].
We used as indicators the nonzero practice of physical activity during leisure-time, transport, and occupational domains considering our aim of estimating the practice of each domain as well as to increase the comparability among the surveys. The sum of the physical activity domains (leisure-time, transport and occupational) was used as an indicator of total physical activity, and we classified as physically active those who reported more than 150 min/week [17]. Sitting time was classified using the cutoff point of 8 hours/d [18]. More information about the specific questionnaires is presented in Table S1 in the Online Supplementary Document.

Indicators of socioeconomic inequalities
Gender (men and women), chronological age (18-34 years, 35-49 years, 50-64 years), and educational level (quintiles or categories) were considered as sociodemographic indicators. We classified educational level into categories based on the years of education, or the highest level of education reached by the individuals in each survey. More information is presented in Table S1 in the Online Supplementary Document.

Statistics
Eight countries were included in the analysis for leisure-time physical activity, while seven countries were included in the analysis of transport, six in the analysis of total physical activity, five in the analysis of occupational physical activity, and six in the analysis of sitting time. We included five surveys from Argentina, four from Brazil, three from Colombia and Peru, and two from Bolivia, Chile, Ecuador, and Uruguay. We used values of frequency and 95% confidence interval to estimate the prevalence of each physical activity domain, total physical activity and sitting time according to each subgroup in every survey. We defined the gap as the absolute difference between the quintiles 5 and 1 of education, between the men and women, as well as between the 18-34 and 50-64 groups of age. All the analyses were conducted using the Stata 15.1 software.

RESULTS
The temporal trends in leisure-time physical activity according to education, gender and age are presented in Table 1. Except for Colombia and Ecuador, leisure-time physical activity increased in all countries, with Brazil (2008 = 27.2% vs 2019 = 42.9%) and Peru (2007/2008 = 24.0% vs 2011 = 40.4%) presenting the largest increases. However, the increase in leisure-time physical activity was not similar among the population groups and the difference between the first and the fifth quintiles of education increased, especially in the highest quintiles of education (Figure 1). Although men and younger adults presented a higher prevalence of leisure-time physical activity, the gender and age inequalities were similar across the surveys, with minor increases for gender inequalities in Chile and Ecuador and age inequalities in Brazil, Chile, Ecuador, and Peru (Figure 1).   and reduced in Ecuador. The inequalities regarding education, gender and age group were minor and similar across the surveys (Figure 1).
The trends of occupational physical activity and inequalities are presented in Table 3. While the prevalence of occupational physical activity increased in Argentina, Brazil, and Uruguay, it decreased in Chile and Peru. The inequalities regarding education quintiles were reduced among all the countries, while the gender inequalities increased in all countries (except Uruguay), and inequalities regarding age groups were maintained over the years (Figure 1).
There were mixed findings for the time trends of total physical activity ( Table 4) (Figure 2). Also, there was increasing gender inequality in Argentina, Chile, and Peru, while the age inequalities were constant over time.
Temporal trends in sitting time are presented in Table 5

DISCUSSION
We aimed to investigate time trends in different domains of physical activity and sitting time in South America as well as the trends in the inequalities regarding education, gender, and age. Our main findings reveal that leisure-time physical activity increased over the years in most South American countries (in six over the eight countries), but the difference in the prevalence of leisure-time physical activity between the first and fifth quintiles of education also increased over time in most of them as well. The findings for transport physical activity were mixed, with no clear changes in the inequalities over the years. The countries presented a decreasing inequality regarding education for occupational physical activity. Two out of seven countries increased total physical activity, while four increased education inequality and three of them increased age inequality considering the general indicator of total physical activity. Also, no clear patterns of changes in high sitting time over the years were observed and the change regarding its inequality was observed only in Uruguay, which reduced the education inequality.
The increasing trend in leisure-time physical activity, as well as maintenance or reduction in the occupational physical activity, are consistent with findings from high-income countries as well as from individual countries as Brazil [10,19], which can be a marker of a transition in the domain that most contribute to total physical activity [20]. Despite the general trends, there were specific trends considering quintiles of education. For leisure-time physical activity, the highest increases were in the highest quintiles of education, consequently increasing inequalities. These findings are in line with previous research regarding the inequalities in leisure-time physical activity [21], in which the inequalities regarding educational level increased over the years in Brazil.
If countries keep with the same strategies or rely on promoting only leisure-time physical activity as they are doing, they may see some improvements, but at the same time, the public investment will sustain or increase inequalities. A possible explanation for this is the reverse equity hypothesis, in which investments and innovations come first to the most privileged populations and consequently would not be the priority, increasing inequalities [22]. Leisure-time physical activity becomes a reflection of social inequalities in most countries. As people with lower income or educational level are more likely to have inflexible jobs (eg, rigid schedules) and spend more time in passive transport by bus or train as they need to move around cities from peripheral areas to downtown or commercial areas, more tailored strategies are required for these groups as they have reduced time for engaging in physical activity or staying with their families. Countries may promote leisure physical activity by making physical activity more accessible in neighborhoods through public programs in streets and parks, such as the 'Ciclovía program' in Colombia or the 'Academia da Cidade' program in Brazil [23,24]. They also have to plan and invest in infrastructure that makes physical activity the easy option when moving around a neighborhood and choosing a place to play or exercise, especially in the most disadvantaged communities [25]. Also, countries should develop specific policies for physical activity and sedentary behavior [26].      The highest decreases or maintenance in occupational physical activity were observed in the lower quintiles of education. Part of the inequalities can be related to the higher levels of occupational physical activity in the group with lower education and possibly, they turned to more sedentary jobs [20]. Although the benefits of occupational physical activity are controversial [27], political willingness is needed for promoting healthier working conditions in all South American countries.
Even with small variations over time, when analyzing the findings for physical activity in transport separately by education quintiles, there were substantial increases in the highest education quintiles in Argentina, Chile, and Peru. In addition, the highest quintiles were the groups that presented the lowest reductions of active transport in Uruguay, as well as are stable in Brazil, while there was a reduction in this behavior in the lowest quintile. Considering that active transport is more practiced among participants with lower education in South American countries [8], there may be a change in active transport culture in this sub-continent, towards a less unequal active transport. A coordination between organizations and governments for promoting cycling and walking for transportation is needed to improve the equality of infrastructure for active transportation. Efforts should not only be focused on facilities or infrastructure, but also speed regulations, speed enforcement cameras, opening streets for pedestrians, while highlighting the potential benefits for local economy and safety for streets users [25,28].
Similarly, we found that the highest increases in occupational physical activity occurred in the highest quintile of education. There are different possibilities for the increase of occupational physical activity. For example, it is possible that the characteristics of the jobs changed over time or even the country passed through an economic crisis that changed the patterns of employment in the population and this should be inferred within the context of each country.
There were minor variations for total physical activity. However, it is worth noting that there was a general trend for increasing the education inequalities in Argentina, Brazil, Chile, and Colombia, possibly indicating that leisure-time physical activity had an important role in the trends over time. Also, it is expected a reduction in the total time of occupational physical activity [20], partly explaining the highest reductions of physical activity in the lowest quintiles of education, which is the group with highest occupational physical activity [8]. We also found a slightly increasing trend for sitting time across the South American countries, with minor changes regarding education, gender, and age inequalities. The increase highlights that despite actions aiming to increase physical activity practice, policies focused on reducing sitting time, especially for leisure-time passive activities such as watching TV, should be formulated, including tackling sitting time in the national policies for health behaviors or physical activity [17,26].
Over time, there were no substantial changes for gender and age inequalities with women practicing lower leisure-time and occupational physical activity and older people presenting lower physical activity in all domains. Gender inequality is a recognized challenge in physical activity research [29,30] and more pronounced public policy actions should be taken to tackle the gender inequalities. Despite the direct actions for increasing physical activity among women as including this in national physical activity plans, other factors may also contribute to reducing gender differences as environmental changes, including the improvement of walkability [31], cycle lanes, access to public transport, and housing density [32]. The present study included more than 550 000 adults from nine out of twelve South American countries to estimate time trends in different domains of physical activity and sitting time in South America, representing approximately 98% of the South American adults, and this is the first study of this kind to our knowledge. However, our findings have limitations that should be considered. First, even though we considered nonzero min/week for the different physical activity domains, there were small variations in the questionnaires in Bolivia, Brazil, Chile, Ecuador, and Peru, which may have changed the findings. However, our focus was on inequalities and there is no plausibility that the changes have affected the inequalities themselves. Second, we interpret inequalities by the differences between the lowest and highest quintiles of education, gender, or between the youngest and the oldest, and possibly a higher prevalence of the indicators can lead to an inflation in the inequalities. However, this method is easy to apply and interpret [33]. Third, despite estimates from Venezuela, trends are based on different surveys in different years rather than individual data. Fourth, the trend for each country covers different periods and different sample sizes and the comparability between the countries should take into consideration the country-specific context of the period (eg, passing through an economic crisis) as it may lead to history bias.

CONCLUSIONS
Our findings suggest that the total physical activity, leisure-time physical activity, and sitting time increased over the years, while there were minor changes for transport and occupational physical activity, with mixed findings across the countries. The socioeconomic inequalities increased over the years for total and leisure-time physical activity in most countries, while were constant for transport, occupational, and sitting time. Also, the gender, and age inequalities were constant over time, with women and older adults presenting lower total, leisure-time, and occupational physical activity. Future South American countries efforts may be warranted to promote physical activity and reduce sedentary time in adults, while addressing inequalities when implementing actions. Also, a continuous surveillance on physical activity and sitting time levels is essential to evaluate the effectiveness of the current strategies for promoting physical activity and reducing sitting time.